Update 101-containers.md (#3440)

src/roadmaps/kubernetes/content/101-containers.md

@@ -1 +1,10 @@
-# Containers
+# Containers
+
+Kubernetes is built on containers, so before learning Kubernetes you should be comfortable running and building containers from scratch.
+
+Visit the following resources to learn more:
+
+* [Docker in 100 Seconds (video)](https://www.youtube.com/watch?v=Gjnup-PuquQ)
+* [Official Docker Tutorial](https://www.docker.com/101-tutorial/)
+* [Docker Curriculum](https://docker-curriculum.com/)
+* [Free 3 Hour Video Course on Docker for Beginners](https://www.youtube.com/watch?v=3c-iBn73dDE)